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Ditch transformation brings new life to subdivision

Posted 20 01 2020

in News

Timber bridges allow contact with the water, and good circulation for cyclists or joggers. The bridges are flanked by historic salvaged wharf beams, sourced from Lyttelton Port
Timber bridges allow contact with the water, and good circulation for cyclists or joggers. The bridges are flanked by historic salvaged wharf beams, sourced from Lyttelton Port
Dunbars Drain project, Christchurch

Transforming a ditch running through a paddock into a naturalised, meandering waterway complete with fish life, footpaths, terraces, native riparian planting and bridges had its challenges, Xteriorscapes’ Chris Owen admits. The biggest was the wet winter, which delayed the Dunbars Drain project in Halswell, Christchurch, for months.

What was a utility drain punching through paddocks now provides a green recreation space through the centre of Milns Park, a 265-home subdivision in south-west Christchurch.

Working with their client, Xteriorscapes developed a vision for the drain’s transformation into a natural, relaxed environment; a calm green space with good opportunities for running and cycling, and plenty of options for people to connect with the water. But first they had to get through a soggy winter.

“We faced a few setbacks,” Owen says. “Right when we should have been planting we couldn’t do anything because of the saturated, heavy soil. I saw one of the civil contractors get bogged up to his gumboots and he had to get his workmate to come dig him out”. 

“The conditions were very sloppy, definitely not a site for the winklepickers. The engineers and contractors faced some real sediment control issues, which was why the project had to go on hold throughout the winter.”

Trying conditions in the middle of a wet winter
Trying conditions in the middle of a wet winter
Terraces connect people with the waterway, using recycled wharf beams and concrete, against a gently sloping lawn
Terraces connect people with the waterway, using recycled wharf beams and concrete, against a gently sloping lawn

Xteriorscapes collaborated with civil engineers, aquatic ecologists and contractors to figure out a new path for the waterway, their design focusing on enhancing its ecological health. Through clever placement of boulders they’ve created lots of nooks and crannies for fish. Good sized native planting helps shade and cool the water in the summer.

“We were fortunate to have a client who saw a lot of value in landscaping. We were mindful that this greenspace was a key recreational area for the development, so we wanted to make the most of it and really showcase the stream as an asset.”

Two bridges and four terraces connect people to the water, with generous lawn areas for them to watch the world go by. For that very reason planting on the bank  was “pulled back, to create places to recline and enjoy”, Owen says.

One of the ingenious parts of the design is a special water feature built to cover an artesian well, emerging from an ugly rusty steel pipe protruding out of the ground. 

“We couldn’t cap the well because it was critical to the flow of the waterway. So working with the contractors, we core-drilled through a boulder, lowered it over the pipe and cut the pipe down to hide it, basically an impromptu water feature. I’d love to claim the idea, but our contractors beat me to it on that one”

Now that plants are established on the banks of the waterway, the acres of mud are but a distant memory, and what was an unassuming agricultural ditch is now a tranquil breathing space.

The stream width and bank gradients vary along the waterway, along with a healthy mix of planting texture, size and colour
The stream width and bank gradients vary along the waterway, along with a healthy mix of planting texture, size and colour